An SON (self organizing network) is a type of key standardization project work of the 3GPP (the 3rd Generation Partnership Project) standards organization during R8/9/10 working periods, and a core concept thereof is to reduce traditional manual operations through an automation process during phases of network planning, deployment, optimization, and maintenance, so as to reduce a maintenance cost of a network operator.
A communications network element has an abnormal working state, where the network element may be a cell or a base station. In this state, the network element cannot provide normal communication services, and a user equipment (UE) residing in the network element cannot establish a communication connection, or a user equipment that is performing communication cannot maintain a communication connection and becomes offline. In addition, the network element is in this abnormal working state due to occurrence of a certain type of serious fault rather than execution of an energy saving operation of the network element. The network element under this situation is referred to as an out-of-service network element. A system needs a capability of automatically detecting the out-of-service network element, to trigger a restoring operation of the out-of-service network element or a deactivation operation of an energy saving network element in real time, so that the network element returns to a normal working state. The process of automatically detecting the out-of-service network element belongs to a scope of self healing (SH) of the self organizing network.
If a network element (a cell or a base station) is out of service, some KPIs of the network element, for example, indicators such as a quantity of access requests, a quantity of served users, and an access success rate, are similar to indicators when the cell meets normal energy saving conditions, and whether a current network element is out of service or can enter an energy saving state needs to be distinguished. Currently, methods for detecting the out-of-service network element place emphasis on implementation inside the base station. Whether a network element is out of service is determined by circularly detecting particular software and hardware inside the base station, an external power supply system, or a network connection, and an alarm that the network element is out of service is reported by the base station. This method is strongly related to implementation of the base station, and is only limited to the base station itself. Another detecting method is that, a network management system periodically collects a KPI (key performance indicator) and/or PM (performance measurement) of the network element, and if a performance indicator such as a RRC (radio resource control) connection establishment success rate, or a session or call drop rate (which may be briefly referred to as a “session/call drop rate” in the following) of the network element exceeds a preset threshold in one or more reporting periods, the network element is believed to be out of service. However, these methods only consider the base station itself, and possibly make the network element be in an out-of-service state for a long time, thereby further prolonging time for determining the out-of-service network element or increasing a probability of determining the out-of-service network element wrongly.
Therefore, due to defects of the above out-of-service determining methods, and that energy saving and out of service are not coordinated and controlled in the prior art, an out-of-service network element may decide by itself to enter an energy saving state after reaching an energy saving condition and become a “normally energy saving” cell; as a result, out-of-service detection and compensation are no longer performed for the network element, thereby causing a serious service fault.